Those are really big cases for that bullet weight. I guess you have a big need for speed. How far are you planning on hunting with this rig?

If this is the only bullet weight you are going to use, 1 in 12 twist will be plenty.

I would suggest you look up data on cases like the RUM/reg 300Wby and compare to the Lazz and Wby. Chances are they is not that much difference in vel. This is simply due to the overbore nature of these big cases. They are even less effective when launching "lighter" bullets.

Balancing max. vel and accuracy may also be a little touchy with these cases. What powders are you planning on using?

Keep an eye on the throating too. Try and keep the throat short enough so that the bullets can be on or just off the lands and feed from your mag. The WBY freebore can make it more difficult to get an accurate rifle.

If nothing else, this rig should get some very high muzzle vel and shoot plenty flat. Sort of like 40gr Vmax in a 22/250.

Well, John, I'm so impressed with this 30 Wolf that I can't imagine going anywhere else.

There's a bunch of info on this site regarding it, so I won't rehash the details, but a superfast 30 cal on a 338 Lapua case might be just your ticket, seeing as you're gonna have a big investment in high-quality 338 Lapua brass anyhow...

I don't think that accuracy has to be bad. You may just not have the fastest vel but a well assembled rig should shoot. If you look at the 30-378 factory loads and handloads, the 180gr bullet can leave at 3400fps and accuracy is excellent. The 165 will be 100 to 150fps faster. As long as twist is around 12, the bullets will not be overspun. I believe this is what causes erratic accuracy - the bullet spinning so fast that it is bending.

The barrel burner concept can work, but is it really necessary. Low BC bullets going fast don't give the same performance as a high BC bullet launched slower at long range.

Consider a 30 cal rig for the 240gr MK or a 338 rig for the 300gr MK. There is lots of info on these cases on this site. They work and work very well out past 1000yds.

John,
If I were you I would go with the Warbird. The .30-378 is nice, but there is a belt, there is the venturi shoulder. Brass for both is very good. I have heard of Lazzeroni brass being reloaded over 20 times. I think Warren told me that with a 29" barrel he could get 3300 fps from a 30-378 with a 220 grain bullet. I would assume that the since Lazz case is a tiny bit smaller that with a 30" barrel you could get about 3300 or 3350. If it were me I could get the Warbird using 220 grain bullets with a 1:8 twist. That isn't necessarily an MK, but a J40 Warren says that would be best. I'm not sure what grain bullet you want to use, but with a case that big I would go with a 220 grain J40 or MK or the 240 MK. I agree with Jerry about accuracy. I can get 1/4" groups at 100 yards with a 220 MK. I could think that a 30" barrel and one of these cases your velocity would be about 3600 or more, then your accuracy might go down. One more thing, I would go with the PGW action since the M700 might be a little "weak" for cases of that size.I hope some of this helps.

If you want to use a 700 action, don't forget about the .300 Tomahawk. We are getting .30/378/Warbird type velocities from the Tommy and the RUM brass is not as bad as everyone makes it out to be.I started with only 60 cases and ended up with 40 that are all within 1 gr. of each other. I weighed 15 loaded rounds the other day for grins and found that they all weightd within .5 gr of 623.5 gr total weight. I have a 30" barrel and am getting aroung 3200 fps from a 240SMK.
I feel it will shoot 175 SMK's in excess of 3700 fps, but since I don't intend to hunt with or shoot this bullet, I don't want to waste barrel life testing it...Good Luck with whatever you decide... Chris

Chris,
if you weigh those twenty other cases with water compared to the other 40, then do the math to compare actual capacity I think you might even be MORE surprised. Mine were ALL within +- .1gr, and that was from three different lots on once fired factory ammo.

Seeings how brass is 8 times denser than water, the extractor groove variance etc can make a huge difference in wt, with the internal capacity still being exactly identical. I weighed each case on the digital scale and wrote the weight on each case with a marker, then weighed them all again after filling them with water from a Visine eye drop bottle, wrote the weight on each one again and subtracted the case wt from each when I was all done. The original case wt was spread out over 4.0gr! Internal wt was about center of that spread and was as I said +-.1gr, I could not believe it! The exact amount of excess wt proved to be on the outside of the case at the base, somewhere that did not affect volume at all. Amazing that they could be THAT close! It took about an hour tops to check 60 cases.

That's pretty surprising Brent, but I can believe it, as the overall weight of my loaded rounds shows. I also found that by going from Fed215 primers to Fed210m's, my ES went from 75 or 80 fps to single digits. imagine that.....

I tried some 210Ms in my 300 Ultra a couple days ago too, they worked fine even at 0 degrees. I never shot them over the Oehler but will next time out. This is the only thing I changed in the good load I have so I'll know right away how they work.

I have a batch of 100 cases I'll check water wt on when they get fireformed too. No sense in putting them in different groups if the internal capacity is the same, like I had been doing. I have seven different groups for my 308win I kept within .5gr of each other, I wonder what they actually measured inside now. Sucks trying to keep things straight when your using so many different groups of cases. I thought I was headed down the same path with the Ultra and only 60rds wouldn't leave many in each group so that's why I decided to check the internal capacity, just to see how much difference there REALLY was because of the 4gr spread.

About the 2 in question. They are both fine cartridges and depending on your reloading tequniques, the Lazzeroni may be a bit more accurate. Also if you are going to hunt big game with either of these cartridges try the "X" bullet in 168. The Sierra's will explode. Have you considered a 190 match?

Does anyone have loading data with the 140 grain lost river bullet in the 30-378 or any big 30. Can it be pushed to 4000 FPS? Looking at a 1-15 twist on it. Am building either an improved lapua, ultramag, 416 or a straight 30-378. Any ideas?

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